src/main/java/dao/StudentDbDAO.java - dev5 - ihaverak/persons

src/main/java/dao/StudentDbDAO.java
128 строк5 KB
ihaverak
лаба 5
23 май 2026, 00:56
23 май 2026, 00:564bb74aa
package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;
import domain.Group;
import domain.Student;
import exception.DAOException;

public class StudentDbDAO implements RepositoryDAO<Student> {

    private static final String SELECT_ALL = 
        "SELECT id, groupid, firstname, lastname, phone, email FROM students ORDER BY lastname ASC";
    private static final String SELECT_BY_ID = 
        "SELECT id, groupid, firstname, lastname, phone, email FROM students WHERE id = ?";
    private static final String INSERT = 
        "INSERT INTO students(groupid, firstname, lastname, phone, email) VALUES(?,?,?,?,?)";
    private static final String EDIT = 
        "UPDATE students SET groupid = ?, firstname = ?, lastname = ?, phone = ?, email = ? WHERE id = ?";
    private static final String DELETE = 
        "DELETE FROM students WHERE id = ?";

    private ConnectionBuilder builder = new DbConnectionBuilder();
    private GroupDbDAO groupDao = new GroupDbDAO();

    private Connection getConnection() throws SQLException {
        return builder.getConnection();
    }

    @Override
    public Long insert(Student student) throws DAOException {
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(INSERT, new String[]{"id"})) {
            Long id = -1L;
            pst.setLong(1, student.getIdGroup());
            pst.setString(2, student.getFirstName());
            pst.setString(3, student.getLastName());
            pst.setString(4, student.getPhone());
            pst.setString(5, student.getEmail());
            pst.executeUpdate();
            ResultSet gk = pst.getGeneratedKeys();
            if (gk.next()) {
                id = gk.getLong("id");
            }
            gk.close();
            return id;
        } catch (Exception e) {
            throw new DAOException(e);
        }
    }

    @Override
    public void update(Student student) throws DAOException {
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(EDIT)) {
            pst.setLong(1, student.getIdGroup());
            pst.setString(2, student.getFirstName());
            pst.setString(3, student.getLastName());
            pst.setString(4, student.getPhone());
            pst.setString(5, student.getEmail());
            pst.setLong(6, student.getId());
            pst.executeUpdate();
        } catch (Exception e) {
            throw new DAOException(e);
        }
    }

    @Override
    public void delete(Long id) throws DAOException {
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(DELETE)) {
            pst.setLong(1, id);
            pst.executeUpdate();
        } catch (Exception e) {
            throw new DAOException(e);
        }
    }

    @Override
    public Student findById(Long id) throws DAOException {
        Student student = null;
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(SELECT_BY_ID)) {
            pst.setLong(1, id);
            ResultSet rs = pst.executeQuery();
            if (rs.next()) {
                student = fillStudent(rs);
            }
            rs.close();
        } catch (Exception e) {
            throw new DAOException(e);
        }
        return student;
    }

    @Override
    public List<Student> findAll() throws DAOException {
        List<Student> list = new LinkedList<>();
        try (Connection con = getConnection();
             PreparedStatement pst = con.prepareStatement(SELECT_ALL);
             ResultSet rs = pst.executeQuery()) {
            List<Group> groups = groupDao.findAll();
            while (rs.next()) {
                Student student = fillStudent(rs);
                Long idGroup = rs.getLong("groupid");
                student.setGroup(groupDao.findById(idGroup, groups));
                list.add(student);
            }
        } catch (Exception e) {
            throw new DAOException(e);
        }
        return list;
    }

    private Student fillStudent(ResultSet rs) throws SQLException {
        Student student = new Student();
        student.setId(rs.getLong("id"));
        student.setFirstName(rs.getString("firstname"));
        student.setLastName(rs.getString("lastname"));
        student.setPhone(rs.getString("phone"));
        student.setEmail(rs.getString("email"));
        student.setIdGroup(rs.getLong("groupid"));
        return student;
    }
}